cast writes to unicode before write

IPython/nbformat/current.py

@@ -1,186 +1,182 b''
 """The official API for working with notebooks in the current format version."""
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
 from __future__ import print_function
 
 import re
 import warnings
 
 from IPython.nbformat.v3 import (
     NotebookNode,
     new_code_cell, new_text_cell, new_notebook, new_output, new_worksheet,
     parse_filename, new_metadata, new_author, new_heading_cell, nbformat,
     nbformat_minor, nbformat_schema, to_notebook_json,
 )
 from IPython.nbformat import v3 as _v_latest
 
 from .reader import reads as reader_reads
 from .reader import versions
 from .convert import convert
 from .validator import validate, ValidationError
 
 from IPython.utils.log import get_logger
 
 __all__ = ['NotebookNode', 'new_code_cell', 'new_text_cell', 'new_notebook',
 'new_output', 'new_worksheet', 'parse_filename', 'new_metadata', 'new_author',
 'new_heading_cell', 'nbformat', 'nbformat_minor', 'nbformat_schema',
 'to_notebook_json', 'convert', 'validate', 'NBFormatError', 'parse_py',
 'reads_json', 'writes_json', 'reads_py', 'writes_py', 'reads', 'writes', 'read',
 'write']
 
 current_nbformat = nbformat
 current_nbformat_minor = nbformat_minor
 current_nbformat_module = _v_latest.__name__
 
 
 class NBFormatError(ValueError):
     pass
 
 
 def _warn_format():
     warnings.warn("""Non-JSON file support in nbformat is deprecated.
     Use nbconvert to create files of other formats.""")
 
 
 def parse_py(s, **kwargs):
     """Parse a string into a (nbformat, string) tuple."""
     nbf = current_nbformat
     nbm = current_nbformat_minor
     
     pattern = r'# <nbformat>(?P<nbformat>\d+[\.\d+]*)</nbformat>'
     m = re.search(pattern,s)
     if m is not None:
         digits = m.group('nbformat').split('.')
         nbf = int(digits[0])
         if len(digits) > 1:
             nbm = int(digits[1])
 
     return nbf, nbm, s
 
 
 def reads_json(nbjson, **kwargs):
     """DEPRECATED, use reads"""
     warnings.warn("reads_json is deprecated, use reads")
     return reads(nbjson)
 
 def writes_json(nb, **kwargs):
     """DEPRECATED, use writes"""
     warnings.warn("writes_json is deprecated, use writes")
     return writes(nb, **kwargs)
 
 def reads_py(s, **kwargs):
     """DEPRECATED: use nbconvert"""
     _warn_format()
     nbf, nbm, s = parse_py(s, **kwargs)
     if nbf in (2, 3):
         nb = versions[nbf].to_notebook_py(s, **kwargs)
     else:
         raise NBFormatError('Unsupported PY nbformat version: %i' % nbf)
     return nb
 
 def writes_py(nb, **kwargs):
     """DEPRECATED: use nbconvert"""
     _warn_format()
     return versions[3].writes_py(nb, **kwargs)
 
 
 # High level API
 
 
 def reads(s, format='DEPRECATED', version=current_nbformat, **kwargs):
     """Read a notebook from a string and return the NotebookNode object.
 
     This function properly handles notebooks of any version. The notebook
     returned will always be in the current version's format.
 
     Parameters
     ----------
     s : unicode
         The raw unicode string to read the notebook from.
 
     Returns
     -------
     nb : NotebookNode
         The notebook that was read.
     """
     if format not in {'DEPRECATED', 'json'}:
         _warn_format()
     nb = reader_reads(s, **kwargs)
     nb = convert(nb, version)
     try:
         validate(nb)
     except ValidationError as e:
         get_logger().error("Notebook JSON is invalid: %s", e)
     return nb
 
 
 def writes(nb, format='DEPRECATED', version=current_nbformat, **kwargs):
     """Write a notebook to a string in a given format in the current nbformat version.
 
     This function always writes the notebook in the current nbformat version.
 
     Parameters
     ----------
     nb : NotebookNode
         The notebook to write.
     version : int
         The nbformat version to write.
         Used for downgrading notebooks.
 
     Returns
     -------
     s : unicode
         The notebook string.
     """
     if format not in {'DEPRECATED', 'json'}:
         _warn_format()
     nb = convert(nb, version)
     try:
         validate(nb)
     except ValidationError as e:
         get_logger().error("Notebook JSON is invalid: %s", e)
     return versions[version].writes_json(nb, **kwargs)
 
 
 def read(fp, format='DEPRECATED', **kwargs):
     """Read a notebook from a file and return the NotebookNode object.
 
     This function properly handles notebooks of any version. The notebook
     returned will always be in the current version's format.
 
     Parameters
     ----------
     fp : file
         Any file-like object with a read method.
 
     Returns
     -------
     nb : NotebookNode
         The notebook that was read.
     """
     return reads(fp.read(), **kwargs)
 
 
 def write(nb, fp, format='DEPRECATED', **kwargs):
     """Write a notebook to a file in a given format in the current nbformat version.
 
     This function always writes the notebook in the current nbformat version.
 
     Parameters
     ----------
     nb : NotebookNode
         The notebook to write.
     fp : file
         Any file-like object with a write method.
-    format : (u'json', u'ipynb', u'py')
-        The format to write the notebook in.
-
-    Returns
-    -------
-    s : unicode
-        The notebook string.
     """
-    return fp.write(writes(nb, **kwargs))
+    s = writes(nb, **kwargs)
+    if isinstance(s, bytes):
+        s = s.decode('utf8')
+    return fp.write(s)